E1762. Hereditary Hemorrhagic Telangiectasia: A Systemic Review
  1. Monica Cooley; Froedtert & The Medical College of Wisconsin
  2. Ashley Norton-Gregory; Froedtert & The Medical College of Wisconsin
  3. Stephane Desouches; Froedtert & The Medical College of Wisconsin
Hereditary Hemorrhagic Telangiectasia (HHT) is a relatively uncommon disorder, with an incidence in North America of 1 in 10,000 (1), that predisposes patients to a variety of vascular dysplasias. The most common presentation of HHT is epistaxis, though other manifestations range from hepatic shunts to cerebral arteriovenous malformations (AVM). The Curacao criteria aid in diagnosis of HHT, and include: 1) recurrent, spontaneous epistaxis; 2) multiple mucocutaneous telangiectasias; 3) involvement of one or more viscera; 4) a first degree relative with a diagnosis of HHT. Patients presenting with 3 of 4 criteria receive a “definite” HHT diagnosis, and patients presenting with 2 of 4 criteria are categorized as “possible” HHT cases. Patients who fail to meet 2 diagnostic criteria are unlikely to have HHT. Radiologists play an important role in the diagnosis and management of HHT, as a sizable proportion of patients have some degree of visceral involvement (2,3). Recognition of these malformations can aid in the diagnosis of HHT, and can also identify treatable lesions in known HHT patients, for whom early intervention may preclude long-term complications, such as bleeding and high-output cardiac failure (4).

Educational Goals / Teaching Points
This exhibit will review the epidemiology and pathophysiology of HHT, as well as criteria for diagnosis, focusing on sites evaluated by the radiologist through an image-rich, case-based approach. After completion of the exhibit, readers will understand the systemic manifestations of HHT and their clinical implications.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Anywhere from 47-91% of HHT patients have gastrointestinal telangiectasias (5), which are more common in the upper GI tract, and 13-30% will experience GI bleeding (6). Though small lesions are typically diagnosed by direct endoscopic visualization, contrast-enhanced CT (CECT) and catheter angiogram may be used to identify sites of active bleeding. Up to 10% of HHT patients may have brain AVMs, depending on phenotype, with over half of these AVMs causing symptoms (7). Current international guidelines recommend MRI with and without contrast, including blood-sensitive sequences, to screen for cerebral AVM in HHT patients (8). Pulmonary AVMs are present in approximately 25% of HHT patients (9), and may lead to hemorrhage, high-output cardiac failure, or paradoxical cerebral emboli. Though these lesions are sometimes seen on chest radiograph, CECT and catheter angiography are used to identify and characterize pulmonary AVMs. Liver involvement in HHT is common, found in up to 74-79% of patients (10). Hepatic pathology includes arteriovenous, arterioportal, and portovenous shunts. Ultrasound is a recommended diagnostic screening tool (8), and CECT and MRI can provide further identification and characterization of various hepatic shunts.

Hereditary hemorrhagic telangiectasia can present with a wide range of symptoms depending upon the organ system(s) involved. Knowledge of the common manifestations of HHT and imaging findings suggestive of the diagnosis can aid the radiologist in providing accurate diagnosis and follow-up recommendations.